Does WD40 remove car scratches? And nine other things we learned testing car scratch removers

We tested nine car scratch removers, including products from Formula 1, T-Cut, JML and Autoglym, to see if they worked and which was the best.

We also tested WD40 to see if it worked at hiding scratches - as the makers of WD40 and countless You Tubers claim

Here are 10 things to remember next time you tackle a troublesome car scratch.

1. WD40 does work...sort of

WD40 stops squeaks, loosens rusted parts, frees sticky mechanisms. But it also hides shallow scratches.

However, we found it takes four applications of WD40 to make a noticeable difference and it will wash away the first time you clean the car.

This makes WD40 a temporary fix until you have time to get to one of the best car scratch removers we discovered through our testing.

2. Most scratch removers only remove shallow scratches

There are three types of scratches that can affect a car panel:

• Shallow scratch A scratch to the clear coat
• Medium scratch A scratch through the clear coat and into the basecoat
• Deep scratch A scratch into the primer or to the metal of the car panel

Most car scratch removers are designed to take care of shallow scratches, scuffs and swirl marks.

A few of the products we tested claimed to be able to make a difference on deep scratches but only one of the nine from our selection had an effect on these.

If you identify a deep scratch on your car it may be time to turn to a professional. Depending on the level of damage, a bodywork repair shop will either be able to smooth it out or, if need be, replace the car panel.

Check out our Which? Trusted Traders for recommended professionals.

How to identify your scratch

If you spot a scratch on your car but can't tell how deep it is by sight, use this easy method to identify it:

Pass your fingernail over the mark. If your fingernail gets caught, this is a medium scratch at least.

With deep scratches, you'll see the primer or metal itself showing through.

3. Paying more doesn't guarantee the best

We tested a range of car scratch removers priced between £4.49 (Mantis Scratch Remover) and £35 (Angelwax Enigma AIO)

While the pricier options did well in our tests, it wasn't the most expensive which did well enough to be named our best car scratch remover.

4. Some repairs don't last long

We investigated whether the car scratch removers we tested would survive a hand wash after their application.

We applied the products, let them dry for a day, and then washed the car panel five times with car shampoo.

For more than half of those we tested, the scratches reappeared before the five washes were up.

• The WD40 washed away with the first treatment
• The repairs from three car scratch removers only survived two washes
• Repairs from two other scratch removers survived three washes
• The repairs from the best products survived all five washes.

5. Washing creates a better finish

Once you've used a car scratch remover that gives you good results, you may nonetheless be dismayed to find the area of bodywork you've worked on left with a bit of a haze.

This duller finish is nothing to worry about. Give your car a once-over with a good polish and you'll be that much happier with the end results.

6. Some are easier to use than others

While none of the car scratch removers we tested were difficult to apply and use, there were certainly several which were easier.

Some of the car scratch removers had caps and lids which made it effortless to get the right amount of formula onto the microfibre cloth for application.

Others seemed to erupt from the bottle as if they had just escaped a one-year lockdown.

We also found the smoother substances were easier to apply than the thicker (more gloopy) products.

7. Preparation is key

One thing we can't recommend highly enough is prepping the area you're going to work on with the car scratch removers.

By prepping we mean washing the car with car shampoo to make sure there's no lurking grit. If this isn't done there is a risk that rubbing a foam pad or microfibre cloth over the area, with grit or sand on it, could make the scratches worse.

8. Avoid using on a sunny day

Giving your car a driveway wash is often a job for a sunny day, so it makes sense to check your freshly cleaned car for any scratches at the same time and, if found, deal with them right away.

However, not all car scratch removers do well when applied in direct sunlight. If this is the case they do say so in their instructions.

9. Take your time

We found many car scratch removers need more than one application to get rid of the shallow scratch.

10. Do a test run

Many of the car scratch removers we tested suggest applying the product to a small out-of-the-way area first. This is to make sure it reacts well with your paint job.

It will say in the instructions if you should do this.